• To evaluate efficacy of chemotherapy regimen.
  

• Overall survival
  
• 2 year progression free survival
  
• Quality of life
  
• Cognitive function
  
• Neurotoxicity
  
• Ototoxicity
  
• Effect of delayed sodium thiosulfate on granulocyte and erythrocyte counts
  
• Polymerase chain reaction examination of csf
  

Rationale: The blood brain barrier is made up of tightly packed cells to protect the brain from toxic materials that might travel up from other parts of the body. However, the blood brain barrier also blocks the delivery of drugs, including therapies for brain tumors. This study includes a combination of chemotherapy agents that might have efficacy against malignant central nervous system lymphoma and a technique called reversible opening of the blood brain barrier. The technique is experimental and might improve the delivery of treatments to the disease in the brain. Through this technique, the blood brain barrier is opened during an angiogram, or blood vessel study of the brain, along with the use of other substances.

Treatment: Patients in this study will receive the following treatments: rituximab (Rituxan), carboplatin (Paraplatin), cyclophosphamide (Cytoxan), etoposide phosphate (Etopophos), and cytarabine (Cytosar-U). A technique called reversible opening of the blood brain barrier will also be performed in patients. For two successive days each month for 12 to 16 months, patients will be admitted to the hospital to receive study treatments and an angiogram. The night before the angiogram, patients will receive rituximab through an intravenous infusion. The next day, an angiogram will be performed with a general anesthetic and catheter placed in an artery in the groin. The catheter will be directed into the neck to one of the arteries going to the brain that supplies the tumor area. A sugar concentration will then be given to open up the blood brain barrier.

During the two days in the hospital, the drugs carboplatin, cyclophosphamide, and etoposide phosphate will be given to patients. An imaging exam will be performed before opening the blood brain barrier and during the angiogram to assess the amount of blood brain barrier opening. At the physician's discretion, patients may undergo chemotherapy without opening the blood brain barrier due to safety issues. Two weeks after the hospital chemotherapy, patients will receive the drug cytarabine. This agent will be given into spinal fluid through a spinal tap or Ommaya reservoir, which is a port that is implanted under the scalp.